MTN Bad Service

I did a upgrade on my phone in July 2023. We are now on thev7th September. Mtn double billed me on my contract phone and still hasn't sorted our my bill. They wanted me to pay R1628 where my bill is only supposed to be R950 which I paid already. It is now the 7th September and my phone is switched off because some consultants insist I still need to pay the outstanding balance of R628. Where I was told in store four times and other consultants over the phone that I was billed incorrectly. My ticket number is req***. Remedy *** this ticket was logged in the store. I am so angry a month later and it's still not sorted and my phone is switched off